Method for the transfer of thin layers of monocrystalline material to a

Abstract

A method for transferring of monocrystalline, thin layers from a first monocrystalline substrate onto a second substrate, which may have a substantially different coefficient of thermal expansion than the first substrate is realized by producing hydrogen-traps in the first substrate by a first implantation and then implanting hydrogen followed by a heat-treatment to weaken the connection between the implanted layer and the rest of the first substrate, then forming a strong bond between the implanted first substrate and the second substrate and finally using another heat-treatment in order to split the monocrystalline thin layer from the rest of the first substrate by the formation, growth and overlapping of hydrogen filled microcracks. In the case of substrates with different thermal expansion coefficients the heat-treatment for splitting must be and can be at a temperature lower than a critical temperature at which the bonded pair degrades due to the mechanical stresses caused by the different expansion coefficients of the bonded-pair structure. In an alternate approach only hydrogen implantation, wafer bonding and splitting steps are used under the additional condition that the hydrogen implantation temperature of must be higher than the temperature at which the transfer of the layer is accomplished.